A potable liquid bottle, such as a water bottle for a water cooler or similar dispenser, is usually provided with a cap to close and seal a discharge opening on a neck of the bottle during storage, transportation, and manipulation of the bottle. Of course, other than water, the potable liquid contained in the bottle can also be juice, soft drink, or any other type of drinkable liquid.
The cap prevents inadvertent spilling of liquid from the bottle and contamination of the liquid by exposure to the environment. The cap also ensures that hygienic conditions exist on surfaces of the neck of the bottle and around the discharge opening on which liquid flowing out of the bottle will come into direct contact with. Typically, the cap is made of a polymer material and includes a tension ring or the like that provides a radial force for retaining the cap on the neck of the bottle. The cap also generally includes a line of weakness that facilitates tearing or rupturing of the cap material by a manual pull when the cap is to be removed from the bottle.
To adequately seal the bottle, the cap may have a nonintegral resilient seal which engages the upper edge of the bottle neck and thus seals the discharge opening. By “nonintegral” is meant a resilient seal that is distinct from the remainder of the cap and mounted to the cap to perform the sealing function. The nonintegral resilient seal can be formed directly on the cap by laying a bead of polymer material which becomes resilient when it sets.
The manufacturing of such a nonintegral seal faces a number of challenges. On one hand, there is the need to reduce as much as possible the amount of polymer material used to form the resilient seal in order to lower the cost of production of the cap. At the same time, when less polymer material is used, the integrity of the resilient seal may be compromised. This is particularly important when the threadless cap is used to close large water bottles that are made of plastic material, where significant dimensional variations can exist between different brands or models of bottles in the area of the bottle neck. For such applications, it is important to provide caps with good sealing ability capable to accommodate bottles with significant dimensional variations.
Accordingly, there is a clear need in the industry to provide an improved threadless cap for closing a liquid bottle that uses a nonintegral cap and that provides an effective sealing function.